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PORTTI Delphi Create as TValue an n-dimensional matrix
 

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  1. PORTTI Delphi Create as TValue an n-dimensional matrix
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    <p>Good day,</p> <p><a href="http://www.delphifeeds.com/postings/60805-tvalue_in_depth" rel="nofollow noreferrer">TValue</a> is a Delphi-2010 and up RTTI feature.</p> <p>Following on from my <a href="https://stackoverflow.com/questions/4561569/rtti-dynamic-array-tvalue-delphi-2010">earlier question</a>, I had tried to make recurrent function to return a TValue as a n-dimensional. matrix(2D, 3D, 4D...)</p> <p>for example, this procedure will show a n-dimensional matrix(it will list all elements from a n-dimensional matrix as TValue variable):</p> <pre><code>Procedure Show(X:TValue); var i:integer; begin if x.IsArray then begin for i:=0 to x.GetArrayLength-1 do show(x.GetArrayElement(i)); writeln; end else write(x.ToString,' '); end; </code></pre> <p>I don't understand how to create a function to create from a TValue an n-dimensional matrix. For example i need a Function CreateDynArray(Dimensions:array of integer; Kind:TTypeKind):TValue; and the function will return a TValue which is a dynamic array how contain the dimenssions for example:</p> <p>Return=CreateDynArray([2,3],tkInteger); will return a TValue as tkDynArray and if i will show(Return) will list</p> <pre><code>0 0 0 0 0 0 </code></pre> <p>Is not terminated. From a TValue i try to create a DynArray with n-dimensions</p> <pre><code>Procedure CreateArray(var Value:TValue; NewDimmension:integer; NewValue2Kind:TTypeKind; NewValue2:TValue; IsLast:Boolean); var i:integer; NewValue:TValue; len:Longint; begin If Value.IsArray then// we have components in this dimension begin for i:=0 to Value.GetArrayLength-1 do// list all begin NewValue:=Value.GetArrayElement[i]; CreateArray(newValue,NewDimension,NewValue2Kind,NewValue2,IsLast); Value.SetArrayElement(i,NewValue); end; end; end else begin if isLast then begin len:=NewDimension; DynArraySetLength(PPointer(Value.GetRefereneToRawData)^,Value.TypeInfo,1,@len); //set length to NewDimension for i:=0 to NewDimension-1 do //Fill all with 0 Value.SetArrayElement(i,NewValue2); end else begin len:=NewDimension; DynArraySetLength(PPointer(Value.GetRefereneToRawData)^,Value.TypeInfo,1,@len);//I will create len TValues end; end; var Index:array of integer; Value:TValue; ValuKind:TTypeKind; ...... ...... .... Case token of tokInt: begin ValueKind:=tkInteger; Value:=0; end; ..... end; Index:=GetIndexFromSintacticTree;//for example if i have int[20][30] index=[20,30] for i:=0 to high(index) do begin if i = high(index) then CreateArray(Variable.Value,Index[i],ValueKind,Value,True) else CreateArray(Variable.Value,Index[i],ValueKind,Value,False) //Variable.Value is TValue end; //first TValue have 1 element, after that it will have 20 elements, and after that will have 20*30 elements </code></pre> <p><img src="https://i.stack.imgur.com/I9ubT.png" alt="The ideea"></p> <p>Thank you very much, and have a nice day!</p>
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    1. COWhat is TValue? What has RTTI have to do with it? Which version of Delphi do you have?
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    2. COThere is a new version for Reflection since Delphi 2010, with this new RTTI theoretic you can do anything.
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    3. COIt's quite hard to find the motivation to get into this question given that it is hard to see why anyone would want to do this. Is there some underlying motivation that goes beyond your personal distaste for Delphi generics?
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      1. USDavid Heffernan
 

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